In recent years, various flat panel displays have gained popular widespread use. A liquid crystal display (LCD) panel is a type of flat panel display device that can be readily mass-produced. The lightness and slimness of LCD panels make them suitable for a wide variety of uses in electronic devices such as personal digital assistants (PDAs), mobile phones, portable personal computers, and other electronic appliances. The liquid crystal of an LCD panel cannot emit light by itself, and so, a backlight module needs to be employed in the LCD panel. In particular, high illumination performance, low power consumption, and a small size are desired. Nowadays, improving the illumination performance has become a key goal for many LCD developers and manufacturers.
In a typical LCD panel, a backlight module provides a surface light source for illuminating the LCD panel. Generally, the backlight module includes a light guide plate and a light source arranged adjacent to one side of the light guide plate. The light guide plate changes light beams received from the light source into surface light beams and directs the surface light beams to a liquid crystal panel of the liquid crystal display.
FIG. 1 shows a conventional backlight module 1 used in an electronic device such as a mobile phone. An electronic device generally includes a LCD panel and a keypad. The backlight module 1 comprises a light guide plate 10 and a point light source 11 deposed adjacent to a corner of the light guide plate 10. The light guide plate 10 includes a light guiding area 105 corresponding to the LCD panel, and defines a plurality of holes 106 corresponding to the keypad and a plurality of curving grooves 107 adjacent to the light guiding area 105. The light guide plate 10 also defines a plurality of grooves 108 around each hole 106 for guiding light. The point light source 11 can emit light beams, and the light beams come out of light guiding area 105 and the hole 106 via the curving grooves 107 and the groove 108 to respectively illuminate the LCD panel and the keypad.
The light guide plate 10 should be assembled to a frame (not shown). Typically, the assembly process is complex, time-consuming, and costly. In addition, the light guide plate 10 and the frame are normally not attached together with a compact fit, thus, exposing gaps that leak light beams emitted from the point light source 11. As a result, the light beams utilization is inefficient and the light guiding area 105 cannot be propagated to its desired effect causing a drop in brightness of the LCD display. Furthermore, because unwanted gaps appears between the light guide plate 10 and the frame, visible bright lines or dark lines occur, causing the brightness distribution of the backlight module 1 to be non-uniform.
What is needed, therefore, is a light guide element and a corresponding backlight module which can provide a more improved brightness and a better uniform brightness distribution.